Peracids, especially per-acetic acid, due to their bactericidal, fungicidal, sporicidal and virucidal effects with environmental reaction products (e.g. per-acetic acid: acetic acid, hydrogen and oxygen ) are often brought into action as disinfectants. Per-acetic acid, particularly, especially in diluted solutions with high temperatures and pH-values decomposes in time. Thus, for the use of peracid containing solutions it becomes necessary to determine the per-acid content with regularity to assure the desired effect.
The quantitative determination of peracid is difficult, because watery peracid solutions always contain hydrogen-peroxide, which shows similar reactions. With titimetric determinations two different reagents are consecutively employed in order to determine quantitatively the contents or the concentration of peracid, e.g. per-acetic acid and hydrogen-peroxide next to each other. EP 0 322 631 B1 offers a method and reaction for the determination of per-acids next to hydrogen-peroxide, whereby a sampling is required. After the mixing of a test solution with the proper reaction-solution in a cuvette, a certain reaction-time will determine the extinction by using a spectro-photometer. The data will be compared with a calibration curve.
This known method requires much time, proper equipment and trained personnel.